PDRN for Hair Regeneration: Clinical Study on Follicle Stimulation (2020)

Key Findings

• PDRN scalp mesotherapy produced a statistically significant increase in hair density (+21.3 hairs/cm², p<0.01) and hair shaft diameter (+12.8%, p<0.05) compared to placebo at 24 weeks ^[1][4].
• Trichoscopic analysis showed a significant increase in anagen-to-telogen ratio in the PDRN group (78:22 vs 61:39 at baseline, p<0.01) ^[4].
• PDRN's mechanism of action via adenosine A2A receptor activation promotes dermal papilla cell proliferation and VEGF-mediated perifollicular angiogenesis ^[2][5].

Abstract

This prospective, controlled clinical study evaluated the efficacy of intradermal polydeoxyribonucleotide (PDRN) injections in the scalp for promoting hair regeneration in patients with androgenetic alopecia (AGA) ^[1][4]. Thirty-six subjects (18 male, 18 female) with Ludwig grade I-II or Hamilton-Norwood grade II-IV AGA received either PDRN (5.625 mg/3 mL) or normal saline via mesotherapy injections into the affected scalp areas over 8 sessions at 2-week intervals ^[1][4]. PDRN is known to activate A2A adenosine receptors, stimulating growth factor release and angiogenesis in target tissues ^[2][5]. Primary endpoints included hair density, hair shaft thickness, and anagen-to-telogen ratio assessed by phototrichogram at baseline, 12 weeks, and 24 weeks ^[4].

Methods

Subjects were randomized 1:1 to receive either PDRN or placebo via intradermal mesotherapy in a standardized scalp injection protocol ^[1][4]. Treatment areas were divided into a grid pattern with injection points spaced 1 cm apart, delivering 0.05 mL per injection site using a 30G needle at a depth of 3-4 mm ^[4]. Phototrichograms were captured at a fixed reference point (mid-frontal or vertex, depending on pattern) at each time point ^[1]. Secondary endpoints included patient self-assessment scores (hair shedding, volume, and overall satisfaction) and investigator global assessment on a 7-point scale ^[4]. Adverse events were documented at each visit.

Results

At 24 weeks, the PDRN group demonstrated significant improvements in all primary endpoints compared to placebo ^[1][4]. Mean hair density increased by 21.3 hairs/cm² in the PDRN group versus 4.7 hairs/cm² in placebo (p<0.01) ^[4]. Hair shaft diameter increased by 12.8% in the PDRN group versus 2.1% in the placebo group (p<0.05) ^[4]. Trichoscopic assessment revealed a shift toward the anagen phase, with anagen ratio increasing from 61% to 78% in PDRN-treated subjects versus 62% to 65% in placebo (p<0.01) ^[4]. Patient satisfaction scores were significantly higher in the PDRN group (7.4 vs 3.8 on a 10-point scale, p<0.001) ^[1][4]. Investigator global assessment showed improvement of at least 1 grade in 72% of PDRN subjects versus 22% of placebo ^[4]. These results are consistent with PDRN's known ability to activate A2A receptors on dermal papilla cells, promoting VEGF release and enhancing perifollicular vascularization, which is critical for hair follicle cycling and growth ^[2][3][5].

Conclusion

This clinical study provides moderate evidence that intradermal PDRN scalp mesotherapy can meaningfully improve hair density, shaft thickness, and follicle cycling in patients with androgenetic alopecia ^[1][4]. The A2A receptor-mediated mechanism supports a biologically plausible pathway for follicle reactivation ^[2][3]. PDRN's favorable safety profile — with no serious adverse events beyond transient injection-site erythema — makes it a promising adjunctive or standalone treatment for hair regeneration ^[1][4][5]. Larger randomized controlled trials with longer follow-up are warranted to confirm these findings and establish optimal dosing protocols.